Door latch



July 12, 1960 H. w. FALK DOOR LATCH Filed Nov. 5, 1956 INVENTOR Harold Ml. Fall! ATTORNEY DOOR LATCH Harold W. Falk, 7425 Pleasant Ave., Minneapolis, Minn.

Filed Nov. 5, 1956, Ser. No. 620,221

'6 Claims. (Cl. 292-422) This invention relates to an improvement in door latches and deals particularly with a simple latch which can be easily and quickly mounted upon a door and which incorporates a simple type of lock capable of locking the door in closed position.

'One of the difiiculties with door latches lies in the fact that they are often difi'icult and expensive to install. Many types of locks require that openings be cut in the edges of the door, keepers be recessed into the door frame, and

that the various parts must be mortised into the body of the door. An object of the present invention resides in the provision of a simple and effective lock which may be applied by merely drilling holes laterally through the door and securing the lock in place thereupon.

A feature of the present invention resides in the provision of a lock, the mechanism of which is mounted in a small housing designed for attachment with the surface of the door near the free edge thereof. This housing is provided with an opening in one side thereof and a tapered latch bolt projects through this open side. This latch bolt is pivotally supported and is-spring urged into projected position. As the door closes, the latch bolt automatically'retracts until it passes a projecting keeper on the door frame. When the door is to be opened, this operation may be accomplished by merely oscillating a handle shaft which extends through the door and which is equipped with suitable handles on opposite sides of the door.

A feature of the present invention resides in the provision of a latch having a latch bolt which is pivotally supported upon a pivot generally parallel to the plane of the edge of the door. The latch bolt is connected to one of a pair of toggle links which overlap and which are hingedly supported at their opposite outer ends. A cam is provided on the latch operating shaft which extends parallel to the pivot supporting the latch bolt. Rotation of the handle shaft in one direction acts to pivot one of the toggle links which acts through the connecting mechanism to move the latch bolt into retracted position. Movement of the handle shaft in the opposite direction operates both of the toggle links thereby retracting the latch bolt in the same manner. The connection between the toggle link and the latch bolt is such that the latch bolt can be retracted without pivoting the toggle links.

A further feature of the present invention resides in the provision of a simple locking means for locking the latch from operation by the operating handle. This lock includes a member connected to the handle shaft for a reciprocating the shaft within suitable limits, thereby moving the latch operating cam into locking engagement with a portion ofthe latch bolt. The arrangement is such that when the cam is in locking position, the handle shaft cannot be rotated. However, means are provided for automatically unlocking the door in the event the latch bolt is retracted. In other words, if the door is locked while in an open position and the door is swung shut, the lock will be automatically released. This arrangement pre- 'vents the accidental locking of the door-as the latch is ice be locked out by accidental operation of the lock as the door is opened or closed.

A further feature. of the present invention resides in the provision of a lock which is extremely simple to form and which is inexpensive to produce. All of the elements of the lock may be inexpensively produced so that the entire mechanism can be constructed at a low cost.

These and other objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claims. I

In the drawings forming a part of the specification:

Figure l is a perspective view of the lock attached to a door showing the general arrangement of parts therein.

Figure 2 is a cross sectional view through a portion of the door showing the manner in which the latch is,

mounted.

Figure 2 but showing the latch in locked position.

Figure 4 is a sectional view taken at right angles through the section of Figures2 and 3 and showing the latch in unlocked position.

Figure 5 is a view similar to Figure 4 latch in locked position.

Figure 6 is a sectional view through the mechanism housing with the closure plate of the mounting removed. t

Figure 7 is a perspective exploded view of several of the parts forming the latch mechanism.

Figure 8 is a perspective view of the cam which is employed for operating the latch bolt.

The door latch is indicated in general by the letter A. The latch mechanism is enclosed within a box-like housing 10 having a top wall 11, a bottom wall 12, and side walls 13 and 14. The latch housing also includes a cover panel 15 which is preferably integral with the side walls. This cover panel 15 is provided with a pair of spaced apertures 16 and 17 which are designed to accommodate machine screws 19 and 20. The enclosure 10 also in-v cludes a central aperture 21 through which the operating shaft and a part of the operating-handle may extend.

As is indicated in Figure 2. of the drawings the mech anism housing 10 is held in place by attachment with an escutcheon plate 22 which overlies the opposite surface of the door B. This escutcheon plate 22 is provided with a pair of spaced internally threaded sleeves 23 and 24. These sleeves are designed to extend through spaced apertures 25 and 26 in the door B and accommodate the mounting screws 19 and 20. Thus the lock is mounted for attachment and removal from one side only'of the door. The escutcheon plate 22 forms a bearing for a sleeve 27 which is attached to the door knob 29, a portion of which is illustrated in Figure l of the drawings.

Secured within the cover panel E5 of the enclosure 10 I provide a mounting plate 30, the constructionof which is best illustrated in Figure 7 of the drawings. The mounting plate 30 is provided with a base panel 31 which extends parallel to the housing cover panel 15 and in surface contact thereto. The base panel 31 is provided with a central aperture 32 extending therethrough, this opening having counter-sunk edges 33; The mounting plate 30 also includes a pair of parallel end panels 34- and 35 secured at opposite ends of the base panel 31 and extending in right angular relation thereto. A pair of channel shaped enclosure members 36 and 37 aresecured with the edges of their channel shaped structure abutting the end panels 34 and 35. Tongues such as,39 are provided on one edge of the enclosure members 36 and 37, these tongues extending through openings 40 in the end wall panels 34 and 35 and being bent over to secure the channels in place to form rectangular en- Patented .lnly 1.2, 1966 showing the.

pivot the latch bolt.

as stops for a pair of toggle levers which will now be described.

The toggle levers 41 and 42 areprovided with hook ends 43 and 44 respectively which extend through slots.

45 and 46 in the end panels as and 35. The toggle lever 41 is provided with a pair of longitudinally extending flanges 47 along opposite longitudinal edges thereof for increasing the. strength of the lever. The lever 42 is similarly provided with longitudinally extending flanges 49 which terminate in spaced relation to the extremity of the lover. The lever 42 is provided with an ofiset end 56 which is designed to overlap the end 51 of the toggle lever 41 when the toggle levers are pivotally supported in their respective slots 45 and 46;

As is indicated in Figure 6 of the drawings, these levers 41 and 42 engage against .a side of the rectangular enclosures 36 and 37 in one extreme pivoted position. The levefs are also engaged by a cam 52 mounted upon the handle shaft 53 of the latch. The handle shaft or operat iiig shaft 53 is multi-sided in form. As is indicated in a Figure 8 of the drawings, the cam 52 includes a bearing plate 54 having slightly offset bearing edges 55 and a pair of right angularly extending cars 56 and 57. The ear 56 is provided with a curved extremity 59 for a purpose which will be later described. The cars 56 and 57 are provided with aligned apertures 60 and 61 through which the shaft 53 extends. The apertures 69 and 61 are shaped similarly to the shaft so that the cam will rotate in unison With the shaft.

The cam 52 is secured in a proper relation to the shaft 53 so as to move longitudinally in conjunction therewith. This is done so that the cam may also serve as a lock for preventing rotation of the handle shaft 53.

As is also illustrated in Figures 6 and 7 of the drawings a pin 62 extends loosely through the toggle lever 42 and also through a pivoted latch bolt 63. The latch bolt 63 is provided with an elongated body portion 64 which is rolled at one end to form a tubular bearing 65 which encircles a pivot post 66 extending upwardly from the base panel 31 of the mounting plate 30. The latch bolt is bulged outwardly to provide a projection 67 which forms a right angular shoulder 69, indicated in dotted outline in Figure 4 of the drawings and providing a tapered surface 70 on its opposite side. The latch bolt 63 is provided with a longitudinally extending reinforcing flange 71 along one edge and a second reinforcing flange 72 having a projection 73 thereupon along its opposite longitudinal edge. The latch bolt '63 terminates in a lip 74 which is designed to engage the wall 14 of the housing to limit eutward pivotal movement of the latch bolt. As is best indicated in Figure 1 of the drawings, the housing wall 14 is provided with an opening 75 through which the locking projection 67 extends.

The pin 62 is provided with a head 76 outwardly of the latch bolt 63 so that a pull upon this pin will act to The pin 62 is also provided with an endshoulder 77 (see Figure 7) which is designed to engage against the toggle lever 42 so that pivotal movement of this toggle lever 42 will act to pivot the latch bolt 63.

A spring 79 encircles the pin 62 between the toggle lever '42 and the latch bolt 63 and a somewhat larger spring 80 is interposed between the toggle lever '42- and the wall 13 of the housing. When the toggle lever '42 is pivoted the cam 52, the spring 80 compresses and the pivotal movement of the toggle lever 42 acts through the pin 62 to pivot the latch bolt 63. However, if the latch bolt should pivot independently as would be the case as the door swung into closed position and the latch bolt eh- I gaged its keeper, the spring 80 will normally hold the toggle lever from movement and the spring 79 will compress to permit relative pivotal movement of the latch bol't. r

' elosiife plate 81 is provided which bridges the end panels of the'mounting plate 36 to form a generally rectangular frame. The ends of this mounting plate 81 are provided with transverse slots 82 and 83' which are designed to accommodate short projecting tongues 84 and 85 on the end panels 34 and 35 of the mounting plate 36. The closure plate 81 is shown in Figures 2 and 3 of the drawings to include tongues 86 which are struck from the plane of the closure plate and extend inwardly therefrom. The ends of these tongues 86 are spaced apart a distance substantially equal to the width of the ear 56 on the cam 52. As was previously described, the cam 52 is mounted upon the handle shaft .53 for longitudinal movement as well as rotary movement therewith. Accordingly, by moving this operating shaft 53 longitudinally from the position shown in Figure 2 to the position shown in Figure 3, the car 56 may be engaged between the tongues 86 and the tongues will accordingly hold the cam and consequently the operating shaft 53 from rotation.

The sleeve 89 extends through the opening 21 in the front panel 15 of the inclosure 10 and through the registering opening 32 in the base panel 31 of the mounting plate 36. The end of this sleeve is turned outwardly or riveted as indicated at 96 to hold the sleeve 89 in place. At least a portion of the sleeve 89 as indicated at 91 fits the contour of the shaft 53 and accordingly the sleeve 89 rotates with the handle shaft 53. A handle 92 is mounted upon the sleeve 69 and rotates in unison there- I with. The handle 92 includes a hearing or barrel porhearing or barrel portion can be rotated With the sleeve 89.

. latch bolt 63.

a The sleeve encircling portion 93 has an aperture therethrough as indicated at 96 which extends entirely through the handle construction. A pair of notches 97 are provided communicating with the aperture 96 and with the outer end of the handle opening 96, the notches 97 being in diametrically opposed relation. A shaft operating member 99 is attached to the end of the handle shaft 53 by means of a screw 100 or other suitable means. This operating member 99 extends into the notches 97 and is held from rotation with respect thereto. The member 99 may move from the position illustrated in Figure 2 of the drawings to the position shown in Figure 3 of the drawings so as to move the cam 52 from the unlocked position shown in Figure 2 to the locked position shown in Figure 3. In the locked position of the sleeve, the ear 56 is engaged between the tongues 86 and the cam and its shaft are prevented from rotation.

When the cam 52 is in the locked position shown in Figure 3 of the drawings, the curved end 59 of the ear 56 is in the path of movement of the projection 73 of the V In the event the latch bolt 63 is pivoted in a counter-clockwise direction as viewed in Figure 6 of the drawings while the cam 52 is in locked position, the projection 73 of the latch bolt will engage the curved surface 59 of the cam and this surface will act as a cam to slide the cam 52 out of locked position.

The operation of the apparatus has to some extent been described in conjunction with the construction of the apparatus. The operating shaft 53 is rotatable in either direction either by the knob 29 or by the arm of the handle 92. If the shaft is rotated in one direction, the upper bearing portion 55 of the cam 52 as viewed in Figure 6 will engage against the toggle lever 41 to pivot this toggle lever in a clockwise direction. As the end of this toggle lever overlaps the end of the toggle lever 42, the toggle lever 42 will be pivoted in a counterclockwise direction. Pivotal movement of the lever 42 acts through the pin 62 to pivot the latch bolt 63 also in a counter-clockwise direction "as viewed in Figure 6. In the event the shaft 53 is rotated in the opposite direction, the lower bearing portion 55 of the cam 52 will engage against the toggle lever 42, pivoting this toggle lever in ber 99 is pushed inwardly, thus moving the cam 52 from the position illustrated in Figure 20f the drawings to the position shown in Figure 3. In this position, the ear 56 of the cam 52 is engaged between the fingers 86 and the cam and accordingly its operating shaft cannot be rotated. The latch may be unlocked by merely pulling the operating member 99 outwardly. However, if the latch is locked accidentally while the door is in an open position, the closing of the door causes the keeper, which has not been shown in the drawings, to engage against the inclined surface 70 of the latch, causing the latch bolt to pivot in a counter-clockwise direction as viewed in Figure 6. The latch bolt is free to retract due to the fact that the connecting rod 62 may slide through the toggle lever 42. As the latch bolt pivots, the projection 73 thereon engages the curved surface 59 of the ear 56 and moves the cam and the operating shaft in an axial direction so as to disengage the ear 56 from the locking tongues 86. With this arrangement the lock cannot be accidentally engaged in a manner to lock the person passing through the door on the outer side of the door.

In accordance with the patent statutes I have described the principles of construction and operation of my door latch, and while I have endeavored to set forth the best embodiment thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

1 claim:

1. A door latch including a latch bolt, means at one end of said latch bolt pivotally supporting the same, a handle shaft supported in parallel relation to the axis of pivotal motion of the latch bolt, a substantially straight lever pivotally supported at one end in substantially parallel spaced relation to said latch bolt and on an axis parallel to the axis of rotation of said latch bolt, cam means on said handle shaft between said latch bolt and said lever and engageable with one end of said lever to pivot the same, and elongated connecting means connecting said lever and said latch bolt to tensionally pull said latch bolt to a retracted position upon pivotal movement of said lever by said cam means when said handle is turned, said connecting means including a pin extending through said latch bolt and said lever, said pin being slidable to permit relative pivotal movement of said latch bolt relative to said lever.

2. The structure of claim 1 and including resilient means between said latch bolt and said lever for urging the same apart.

3. The construction of claim 1 and including resilient means between said latch bolt and said lever for normally urging the same apart, and resilient means engaging said lever to resist pivotal movement thereof.

4. A door latch including a latch bolt element, means pivotally supporting said latch bolt element, a pair of substantially straight toggle lever elements of generally the same length pivotally supported at their remote ends for pivotal movement on axes substantially parallel to the axis of said latch bolt element, a handle lever pivotally supported on an axis parallel to the pivot axis of said latch bolt element, a cam on said handle lever, bearing means on said cam engaging one of said toggle levers at the end thereof adjacent the other toggle lever upon pivotal movement of said cam in one direction and engaging the adjacent end of the other of said toggle levers upon pivotal movement in the other direction, said other toggle lever element overlapping said one toggle lever element with the overlapping portion thereof lying between the cam and the end portion of said other toggle lever so that pivotal movement of said one toggle lever will also pivot said other toggle lever, and connecting means extending through said other toggle lever element and said latch bolt element limiting the separation thereof whereby pivotal movement of said other toggle lever element will also pivot said latch bolt element, said connecting means being slidable relative to at least one of the elements through which it extends whereby pivotal movement of said latch bolt element may be effected without pivotal movement of said other toggle lever.

5. The structure described in claim 4 and including resilient means interposed between said other toggle lever element and said latch bolt element.

6. The construction described in claim 4 and including resilient means interposed between said other toggle lever element and said latch bolt element and including resilient means holding said other toggle lever element from pivotal movement.

References Cited in the file of this patent UNITED STATES PATENTS 450,669 Giese Apr. 21, 1891 455,949. Page July 14, 1891 649,706 Phelps May 15, 1900 770,542 Slaymaker Sept. 20, 1904 1,755,434 Ellingson Apr. 22, 1930 2,163,957 Murrin June 27, 1939 2,302,165 Anderson Nov. 17, 1942 2,420,083 Lickteig May 6, 1947 2,534,693 Adams Dec. 19, 1950 2,666,320 Teich Jan. 19, 1954 2,743,600 Heyer May 1, 1956 

